This invention deals generally with exercise devices and more specifically with a footstool type device which subjects the user""s feet and ankles to a swinging motion.
There is significant interest developing in swinging exercise devices that are virtually unknown in mainstream culture. The devices look very much like footstools except that they typically have two depressions in their top surface, and the depressions are shaped like half cylinders. The devices are actually swinger devices, and they are used to swing the user""s feet and ankles. The footrest of the device is set on top of a swinger enclosure; the footrest cushion is typically a soft material covered by vinyl; and the two half cylinder depressions are used to support the user""s feet or ankles. The devices are used by resting on a flat surface and placing the feet or ankles on the support depressions on the footrest cushion while supplying electrical power to a swinging assembly within the enclosure which supports the footrest cushion.
Several patents have been granted on such devices. U.S. Pat. Nos. 5,468,215 to Park, 5,411,469 to Wang, and 5,328,433 to Lee all show parallelogram structures which are used to move the footrest back and forth. However, all of these prior art devices lack one feature. None of the prior art patents suggest any means for varying the amplitude of the vibration to which the user is subjected although such an adjustment would be very desirable. The ability to adjust the vibration amplitude would be very helpful for users such as those who are arthritic or have limited mobility for other reasons, and to whom the fixed amplitudes now available are excessive. With a means to adjust the amplitude of the vibration, such users can initially use a smaller amplitude vibration, and, as their range of mobility increases they can adjust the swinger to have a greater amplitude.
The present invention provides a foot and ankle swinging device with the capability of changing the amplitude of oscillation. The foot swinger is built upon a horizontal support base which acts as the bottom of the swinger enclosure and the support structure for all the other components. The mechanism which produces the oscillatory motion for the footrest cushion is supported from the upper portion of a vertical support plate extending from side to side in the swinger. The actual motion produced within the swinger is also side to side, that is, in a direction parallel to the diameters of the two half cylinder depressions in the padded footrest of the swinger and across the direction of the legs of the user. Thus the motion imparted to the user""s ankles is a motion transverse to the normal walking motion of the legs.
The swinger structure is based upon a swing-like parallelogram structure hung from the vertical support structure located approximately midway between the front and back of the swinger. In the preferred embodiment, the vertical support structure is a plate which has two bearings attached near the top of the vertical plate with the two bearings separated by a substantial portion of the width of the swinger. A swinging arm is hung from each of these bearings. The arms are of equal length, their bottom ends approach the bottom support base plate of the entire unit, and a pivot point is attached near the bottom of each arm with the pivot points at equal distances from the bearings. A bridge structure spans the distance between the swinging arms and is attached to the arms at their pivot points. Thus, the arms and bridge structure form a parallelogram and can swing back and forth together and move the bridge structure back and forth in a path parallel to the vertical support structure and side to side of the swinger.
Motion is imparted to the parallelogram through a speed reducing gearbox by an electric motor. In the preferred embodiment, the motor is located on the opposite side of the vertical support structure from the parallelogram structure, and the drive shaft protrudes through the vertical support structure. The drive shaft has a rotating cam attached, and a drive link is attached between the rotating cam and one of the swinging arms of the parallelogram structure. The attachment point of the drive link to the rotating cam is offset from the rotating shaft by a short distance. Thus, as the drive shaft and cam rotate, the point at which the drive link is connected to the swinging arm moves back and forth a distance which is twice the offset between the drive shaft and the point at which the drive rod is connected to the cam. The entire parallelogram structure then moves back and forth a distance determined by the point at which the drive link is attached to the swinging arm. In the preferred embodiment of the invention the motion of the parallelogram and the foot cushion is variable between 1xe2x85x9 and 1⅝ inches.
It is this variability of the oscillation amplitude which is not available in the prior art devices. The adjustment of the oscillation amplitude is accomplished quite simply by either of two mechanisms. In one, the cam simply has several connection points, such as holes, at different distances from its connection point to the drive shaft, and the adjustment is accomplished by moving the drive link connection from one hole to another. As the connection point is changed the oscillatory motion changes by twice the distance between the two connection holes. Thus, all that is required to change the amplitude of the oscillation is to open the case of the swinger assembly, remove the nut on the screw holding the drive link to the cam, and change the hole in the cam at winch the drive link is connected.
The second method of changing the amplitude of oscillation is also very simple. It only involves moving the connection point between the drive link and the swinging arm closer to or farther away from the point at which the swinging arm is connected to its top bearing at the vertical support plate. This is facilitated by several holes formed along the length of the swing arm so that the bolt connecting the drive link can be moved from one hole to another to change the amplitude of oscillation.
These simple changes can easily be accomplished by the average user of the foot swinger, and since it is not a frequently required change, the several steps to accomplish it are not a hardship.